Researchers found the BT deal rose by 67 per cent, the Sky deal increased by 53 cent, the EE deal went up by 36 per cent and the Talk Talk deal rose by 28 cent. There was no increase when the Virgin Media deal ended.

On average the broadband bills rose by 43 per cent, or £9.45 more a month, adding £113 a year.

The charity also surveyed more than 3000 broadband customers and found they stayed on the same contract for an average of four years.

It found that pensioners were more than twice as likely than customers under 65 to have been on the same ­contract for more than 10 years.

Similarly, those on low incomes were almost three times more likely than high earners to remain in a contract for 10 years or more.

Mr Guy said: “The Government has rightly put energy firms on a warning for how they treat loyal customers – the actions of broadband firms warrant similar scrutiny.

“Extra protections for ­vulnerable consumers are also a must.”

Earlier this year, BT announced price rises for many of its services, including regular and super-fast broadband. Sky, Virgin Media and TalkTalk also put up prices in the last year.

A spokesman for the ­Department for Culture, Media and Sport said: “We will shortly be consulting on how to improve things further for consumers.”